EPPO Global Database

EPPO Reporting Service no. 03 - 2020 Num. article: 2020/062

Pistia stratiotes in Slovenia

Pistia stratiotes (Araceae: EPPO A2 List)is a popular ornamental plant in aquaria and gardens ponds.   However, since its introduction into the EPPO region, the species has shown invasive tendencies and it can form mats over waterbodies that can negatively affect native biological diversity.   P. stratiotes was first observed in an oxbow lake (a thermal water body) along the Sava River in Southeast Slovenia in 2001, and each spring, the species spreads to cover almost the whole surface of the lake. When comparing historic indigenous macrophyte records and comparing these to surveys conducted in 2011, only a third of previously recorded indigenous species were identified. However, these species were only recorded in areas (6 %) where P. stratiotes did not occur on the lake.   Three species that disappeared are listed on the Red data list: Myriophyllum spicatum (vulnerable) and Najas marina (vulnerable) and Potamogeton trichoides (endangered).  With climate change, other areas within the EPPO region may become suitable for the establishment of P. stratiotes which will threaten indigneous species.  Control and management of the species is essential to prevent to loss of native biodiversity.  


Jaklič M, Koren Š, Jogan N (2020) Alien water lettuce (Pistia stratiotes L.) outcompeted native macrophytes and altered the ecological conditions of a Sava oxbow lake (SE Slovenia). Acta Botanica Croatica, DOI: 10.37427/botcro-2020-009.